EP3942867B1

EP3942867B1 - A system for connecting a telecommunication terminal to a national network and corresponding secure element and terminal

Info

Publication number: EP3942867B1
Application number: EP20710535.4A
Authority: EP
Inventors: Jean-François Gros; Ly Thanh Phan; Vincent Dany
Original assignee: Thales DIS France SAS
Current assignee: Thales DIS France SAS
Priority date: 2019-03-18
Filing date: 2020-03-17
Publication date: 2024-04-24
Anticipated expiration: 2040-03-17
Also published as: MX2021011257A; US20220191677A1; WO2020187866A1; EP3713309A1; US11974353B2; EP3942867A1

Description

The invention concerns telecommunications and more precisely a system permitting to lower the cost for a MNO (Mobile Network Operator) when one of his subscribers is in a situation of national roaming.
In the scope of the invention, a secure element, like a USIM or more generally other xUICC (Universal Integrated Circuit Card) products (embedded or not, like e-UICCs (embedded UICCs) or i-UICCs (integrated UICCs). xUICCs embed USIMs (Universal Sim applications) and cooperate with telecommunication terminals in order to communicate in a 2G, 3G, 4G or 5G network.
The telecommunication terminals are typically handsets, mobile phones, smartphones, PDAs M2M mobile devices or loT mobile devices.
Each secure element or each terminal comprises a plurality of files and especially files in which MCC/MNC (Mobile Country Code / Mobile Network Code) codes of MNOs are stored. These codes define a PLMN. A PLMN is a Public Land Mobile Network, each MNO providing mobile services having its own PLMN.
Different types of PLMNs exist, among them:

HPLMN : Home PLMN
- Derived from IMSI
- IMSI (not more than 15 digits) = PLMN ID + MSIN = MCC + MNC + MSIN
EHPLMN : Equivalent PLMN
- Stored in USIM EF_EHPLMN
  Regarded by the UE (User Equipment = terminal + secure element as equivalent to each other for PLMN selection;
- UE shall update or delete this list at the end of each attach or combined attach or tracking area updating or combined tracking area updating procedure.
- When the UE is switched off, it shall keep the stored list so that it can be used for PLMN selection after switch on.
UPLMN : User Controlled PLMN
- Stored in USIM in EF_PLMNwACT
OPLMN : Operator Controlled PLMN
- Stored in USIM in EFOPLMNwACT
VPLMN : Visitor PLMN
- Given by Physical Layer Search.
FPLMN : Forbidden PLMN
- Stored in USIM in EF_FPLMN

The terminal has two PLMN Selection modes, as described for example in 3GPP TS 23.122 V8.2.0:

Automatic PLMN Selection
Manual PLMN Selection

For the automatic PLMN Selection Mode:

Either the HPLMN (if the EHPLMN (in USIM) list is not present or is empty) or the highest priority EHPLMN that is available (if the EHPLMN list is present).
Each PLMN/Access Technology combination in the "User Controlled PLMN Selector with Access Technology" (UPLMNwACT) data file in the USIM (in Priority Order).
Each PLMN/Access Technology combination in the "Operator Controlled PLMN Selector with Access Technology" (OPLMNwACT) data file in the USIM (in Priority Order).
Other PLMN/Access Technology combinations with received high quality signal received in the random order.
Other PLMN/Access Technology combinations in order of decreasing signal quality.

The exceptions are:

If the UE is in Automatic Network selection mode and if finds coverage of an EHPLMN, the UE may register to the highest priority EHPLMN available and not return to the registered PLMN or equivalent PLMN.
If the EHPLMN list is not present or is empty, and the HPLMN is available, the UE may register on the HPLMN and not return to the registered PLMN or equivalent PLMN.
The Operator shall be able to control by USIM configuration whether an UE that supports this option is permitted to perform this alternate behavior.

Figure 1 shows four files stored in a secure element 10:

An IMSI file EF IMSI (EF meaning Elementary File) storing the IMSI of the subscription. Here the MNO is for example Orange France (MCC = 208 for France and MNC = 201 for Orange, xxx being the MSIN);
An EHPLMN file EF EHPLMN storing a list of PLMNs that are considered as equivalent to the Home Network;
An OPLMNwAcT / PLMNwAcT file storing a list of PLMNs that the terminal shall select in priority when roaming abroad, this list being defined by priority order;
A HPPLMN file defining the interval of time between searches by the terminal for a higher priority PLMN.

This configuration is valid for a 3G network ongoing (4G, 5G).
The problem is the following: In the secure element 10 (or in the terminal) there are these dedicated files in order to ensure that the terminal connects to the preferred Mobile Network when the user travels abroad (roaming situation). Those files are called "OPLMN" (Operator Public Land Mobile Network) and "PLMN" (User controlled PLMN). When in roaming situation (connected to a mobile network outside the home country), the terminal periodically checks if the home network (to which the subscription belongs to, as defined in the file called "IMSI") is available. If it is available the terminal will automatically reconnect to its home network to avoid unnecessary roaming costs. The interval of time between each check is defined in HPPLMN.
In case the home network does not cover the whole country, it is necessary for the mobile operator to build partnership with other mobile network operators and have a "national roaming" if legally authorized by country regulations. In this case there is the file called EHPLMN (Equivalent PLMN) that lists the mobile operators that are equivalent to the home network (in case for example one mobile operator acquires another one, both are considered as "equivalent" from terminal selection perspective). Once the terminal attaches to a mobile operator part of the EHPLMN, the handset stays connected to it until it is no longer available. The problem is that if ever a mobile network operator has to build "national" roaming agreements, then he has two solutions:

Put the national roaming partner in the OPLMN file. But in this case the terminal will consider it is roaming internationally and will then display the roaming logo on the screen of the terminal and switch off the data if the user has disabled data in roaming situation (like users generally do to avoid bill shocks). The user experience is bad and the user usually then calls the MNO call center. This represents a cost for the MNO (manpower for answering the calls) and leads to a bad user experience.
Put the national roaming partner in the EHPLMN file. But in that case the terminal will stay connected to the national roaming partner which is not cost effective for the Home MNO.

The publication US 2019037484 A1 discloses methods of initiating a search for a home network in a mobile device that is attached to a network other than a home network of the mobile device.
The invention has the purpose to propose a solution to this problem.
More precisely, the invention's objective is to enable the mobile operator to provide continuity of mobile services to its users by allowing its users to transparently roam to partner operators in its home country, and to ensure the terminal re-attaches to the home network as soon as it is available. This avoids unnecessary roaming cost and delivers a seamless user experience.
For this purpose, the invention proposes a system comprising a secure element cooperating with a telecommunication terminal, the secure element or the terminal comprising files in which MCC/MNC codes of MNOs are stored, the telecommunication terminal being configured to select the files in order to try to attach the terminal to the telecommunication network of a MNO, the secure element or the terminal also comprising a file, called National like network file, storing national network codes of networks of the country of the Home PLMN of the secure element, the terminal selecting the National like network file in order to try to connect the terminal to one of the networks referenced in the National like network file, the terminal being configured to regularly check whether Home PLMN or a PLMN present in the EHPLMN file is available, if the EHPLMN file exists, in order to connect the terminal to the Home PLMN or to the PLMN of the EHPLMN file.
Preferably, the terminal is configured to not display a roaming logo on the screen of the terminal when the terminal is connected to one of the networks referenced in the National like network file.
Advantageously, the terminal is configured to display on the screen of the terminal the name of the Home PLMN when the terminal is connected to one of the networks referenced in the National like network file.
Preferably, the terminal is configured to enable data service when the terminal is connected to one of the networks referenced in the National like network file.
The terminal is advantageously configured to select successively the following files if the files exist in the secure element or in the terminal:

the EHPLMN file;
the National like network file;
the file containing PLMNs of foreign countries.

The invention also concerns a telecommunication terminal being intended to cooperate with a secure element, the terminal or the secure element comprising files in which MCC/MNC codes of MNOs are stored, the telecommunication terminal being configured to select the files in order to try to attach the terminal to the telecommunication network of a MNO, the secure element or the terminal also comprising a file, called National like network file, storing national network codes of networks of the country of the Home PLMN of the secure element, the terminal selecting the National like network file in order to try to connect the telecommunication terminal to one of the networks referenced in the National like network file, the terminal being configured to regularly check whether Home PLMN or a PLMN present in the EHPLMN file is available, if the EHPLMN file exists, in order to connect the terminal to the Home PLMN or to the PLMN of the EHPLMN file.
The terminal is preferably configured to not display a roaming logo on the screen of the terminal when the terminal is connected to one of the networks referenced in the National like network file.
Advantageously, the terminal is configured to display on the screen of the terminal the name of the Home PLMN when the terminal is connected to one of the networks referenced in the National like network file.
Preferably, the terminal is configured to enable data service when the terminal is connected to one of the networks referenced in the National like network file.
Advantageously, the terminal is configured to select successively the following files if the files exist in the secure element or in the terminal:

The invention will be better understood by reading the following description of a preferred embodiment of the invention in regard of the figures that represent:

Figure 1 a secure element 10 storing different files;
Figure 2 a secure element comprising two new files used for national roaming purposes.

Figure 1 has been described in regard of the state of the art.
Figure 2 represents a secure element 20 comprising two new files used for national roaming purposes. These files are called NLPLMN and HPNLPLMN.
The invention consists in adding to the existing files a new file called NLPLMN (for National Like PLMN) and HPNLPLMN (for High Priority National Like PLMN) in the secure element 20 (or in the terminal cooperating with this secure element 20.
The NLPLMN file comprises a list of mobile networks which will be considered as national partner (they may not be necessarily from the home country to illustrate for example Europe where users can travel abroad with no roaming costs). The list is set in priority order. The NLPLMN file comprises optionally associated access technology.
The PLMNs in this list have typically the same country code as the home PLMN (HPLMN). However, for near border use cases, the country code of these PLMNs could be different.
The HPNLPLMN file comprises the interval of time between searches for network re-selection when the terminal is attached to a National like network (a network comprised in the NLPLMN file).
These two files are preferably stored in the secure element's 20 file system.
The method of the invention consisting in the selection of a network can for example be the following (the network selection process is changed regarding the state of the art):

At attachment, the terminal selects in order:
1. 1. The Home network (present in the EF IMSI file);
2. 2. An Equivalent network (present in the EF EHPLMN file), this list being set in priority order;
3. 3. A National like network (present in the EF NLPLMN file), this list being also set in priority order;
4. 4. A Roaming network (present in the EF PLMNwAcT, EF OPLMNwAcT), this list being also set in priority order.

Of course, as defined by the standard, the EHPLMN file and the PLMNwAcT and OPLMNwAcT files are facultative. In this case, steps 2 and 4 are facultative.

When the terminal is connected to a National like Network, after each interval of time defined in the HPNLPLMN file or the HPPLMN file if the HPMLPLMN is not present, the terminal launches a re-selection of a PLMN with the same priority as defined during the attachment process described above.

This ensures that when a terminal is connected to a National like network, it will try to reconnect to the Home network or to an Equivalent network (an equivalent network is a network with which the Home network has signed an agreement for not charging extra fees for the subscriber).
In contrast, the state of the art only proposed to execute successively steps 1, 2 and 4 (step 3 is absent in the prior art).
So the invention proposes a complete system comprising a secure element 20 cooperating with a telecommunication terminal, the secure element 20 or the terminal comprising files in which MCC/MNC codes of MNOs are stored, the telecommunication terminal being configured to select the files in order to try to attach the terminal to the telecommunication network of a MNO, the secure element 20 or the terminal also comprising a file, called National like network file, storing national network codes (MCC/MNC) of networks of the country of the Home PLMN of the secure element 20, the terminal selecting the National like network file in order to try to connect the terminal to one of the networks referenced in the National like network file, the terminal being configured to regularly check whether Home PLMN or a PLMN present in the EHPLMN file is available, if the EHPLMN file exists, in order to connect the terminal to the Home PLMN or to the PLMN of the EHPLMN file.
The terminal is preferably configured to not display a roaming logo on the screen of the terminal when the terminal is connected to one of the networks referenced in the National like network file. So, the user will not believe that he is connected to a foreign network. It is also possible to configure the terminal to display on its screen the name of the Home PLMN when the terminal is connected to one of the networks referenced in the National like network file.
The terminal can also be configured to enable data service when it is connected to one of the networks referenced in the National like network file.
If the following different files exist in the secure element or in the terminal, the latter can be configured to select successively the following files in the secure element 20:

Finally, the invention proposes a telecommunication terminal being intended to cooperate with a secure element 20, the terminal or the secure element 20 comprising files in which MCC/MNC codes of MNOs are stored, the telecommunication terminal being configured to select the files in order to try to attach the terminal to the telecommunication network of a MNO, the secure element 20 or the terminal also comprising a file, called National like network file, storing national network codes (MCC/MNC) of networks of the Home PLMN of the secure element 20, the terminal selecting the National like network file in order to try to connect the telecommunication terminal to one of the networks referenced in the National like network file, the terminal being configured to regularly check whether Home PLMN or a PLMN present in the EHPLMN file is available, if the EHPLMN file exists, in order to connect the terminal to the Home PLMN or to the PLMN of the EHPLMN file.
The terminal according to the invention is preferably configured to not display a roaming logo on its screen when the terminal is connected to one of the networks referenced in the National like network file.
The terminal is preferably configured to display on the screen of the terminal the name of the Home PLMN when the terminal is connected to one of the networks referenced in the National like network file.
Advantageously, the terminal is configured to enable data service when the terminal is connected to one of the networks referenced in the National like network file.
Preferably, the terminal is configured to select successively the following files if the files exist in the secure element 20 or in the terminal:

The terminal (or mobile equipment ME in general) is capable of:

Reading the USIM new EFs (i.e. EF_NLPLMN and EF_HPNLPLMN);
Using the new EF to perform National Like roaming process.

The National Like roaming process consists in the terminal:

Attaching to a National Like PLMN without considering it is roaming (i.e. no roaming logo is displayed. It is not considered as international because it is part of home mobile network subscription plan)
Performing regularly checks if the home network (EF IMSI /EHPLMN) is available or a network having a higher priority is available.
If available then the handset re-selects automatically the home network or equivalent home network or the higher priority network.

When attached to a network part of the EF NLPLMN, a network is considered having a higher priority when it is the home network, a network part of equivalent network file, or national like network with higher priority (higher in the priority list) during the check above process, the ME checks if higher priority NLPLMN are available.
The new process of network selection consists in the ME performing the following method:

At attachment, the handset would check in the following priority order the availability of a mobile network:
- Home MNO (EF IMSI)
- Equivalent MNO (EF EHPLMN)
- National like roaming (new file: EF NLPLMN)
- International roaming (EF OPLMN)
When attached to a network part of EF NLPLMN, it performs the National Like roaming process (see above).

The invention enables low cost national roaming with dedicated national like USIM file The equivalent HPLMN list allows provision for multiple HPLMN codes, PLMN codes that are present within this list shall replace the HPLMN code derived from the IMSI for PLMN selection purposes. This list is stored on the USIM and is known as the EHPLMN list. The EHPLMN list may also contain the HPLMN code derived from the IMSI. If the HPLMN code derived from the IMSI is not present in the EHPLMN list then it shall be treated as a Visited PLMN for PLMN selection purposes.
As indicated in 3GPP TS 22.011 version 14.8.0 Release 14, it shall be possible for the home network operator to identify alternative Network IDs as the HPLMN. It shall be possible for the home network operator to store in the USIM an indication to the UE that a group of PLMNs are treated as the HPLMN regarding PLMN selection. Any PLMN to be declared as an equivalent to the HPLMN shall be present within the EHPLMN list and is called an EHPLMN. The EHPLMN list replaces the HPLMN derived from the IMSI. When the EHPLMN list is present, any PLMN in this list shall be treated as the HPLMN in all the network and cell selection procedures.

Claims

A system comprising a secure element (20) cooperating with a telecommunication terminal, said secure element (20) or said terminal comprising files in which Mobile Country Code / Mobile Network Code codes of Mobile Network Operators are stored, said telecommunication terminal being configured to select said files in order to try to attach said terminal to the telecommunication network of a Mobile Network Operator, characterised in that said secure element (20) or said terminal also comprises a file, called National like network file, storing national network codes of networks of a country of a Home Public Land Mobile Network of said secure element (20), said terminal selecting said National like network file in order to try to connect said terminal to one of the networks referenced in said National like network file, said terminal being configured to regularly check whether said Home Public Land Mobile Network or a Public Land Mobile Network present in a Equivalent Public Land Mobile Network file is available, if said Equivalent Public Land Mobile Network file exists, in order to connect said terminal to said Home Public Land Mobile Network or to said Public Land Mobile Network of said Equivalent Public Land Mobile Network file.
A system according to claim 1, wherein said terminal is configured to not display a roaming logo on a screen of said terminal when said terminal is connected to one of the networks referenced in said National like network file.
A system according to any of the claims 1 and 2, wherein said terminal is configured to display on the screen of said terminal the name of said Home Public Land Mobile Network when said terminal is connected to one of the networks referenced in said National like network file.
A system according to any of the claims 1 to 3, wherein said terminal is configured to enable data service when said terminal is connected to one of the networks referenced in said National like network file.
A system according to any of the claims 1 to 4, wherein said terminal is configured to select successively the following files if said files exist in said secure element (20) or in said terminal:
- said Equivalent Public Land Mobile Network file;

- said National like network file;

- the file containing Public Land Mobile Networks of foreign countries.
A telecommunication terminal being intended to cooperate with a secure element (20), said terminal or said secure element (20) comprising files in which Mobile Country Codes / Mobile Network Codes of MNOs are stored, said telecommunication terminal being configured to select said files in order to try to attach said terminal to the telecommunication network of a Mobile Network Operator, characterised in that said secure element (20) or said terminal also comprises a file, called National like network file, storing national network codes of networks of a country of a Home Public Land Mobile Network of said secure element (20), said terminal selecting said National like network file in order to try to connect said telecommunication terminal to one of the networks referenced in said National like network file, said terminal being configured to regularly check whether said Home Public Land Mobile Network or a Public Land Mobile Network present in a Equivalent Private Land Mobile Network file is available, if said Equivalent Public Land Mobile Network file exists, in order to connect said terminal to said Home Public Land Mobile Network or to said Public Land Mobile Network of said Equivalent Public Land Mobile Network file.
A terminal according to claim 6, wherein said terminal is configured to not display a roaming logo on a screen of said terminal when said terminal is connected to one of the networks referenced in said National like network file.
A terminal according to any of the claims 6 and 7, wherein said terminal is configured to display on the screen of said terminal the name of said Home Public Land Mobile Network when said terminal is connected to one of the networks referenced in said National like network file.
A terminal according to any of the claims 6 to 8, wherein said terminal is configured to enable data service when said terminal is connected to one of the networks referenced in said National like network file.
A terminal according to any of the claims 6 to 9, wherein said terminal is configured to select successively the following files if said files exist in said secure element (20) or in said terminal:
- said Equivalent Public Land Mobile Network file;

- said National like network file;

- the file containing Public Land Mobile Networks of foreign countries.